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Tuesday, June 22, 2010

Cosmic Log - Lucy's 'great-grandfather' found

A sculptor's rendering shows how the 3.2-million-year-old hominid called Lucy might have looked in life. A more recently found fossil known as Kadanuumuu is from the same species, but 400,000 years older.

Anthropologists say they have discovered the 3.6 million-year-old partial skeleton of a creature that came from the same species as Lucy, but was 400,000 years older and at least as good at walking upright. Their analysis suggests that upright walking, the trademark trait for humans and their extinct kin, goes back further in time than some might have assumed.

This skeleton, described in the Proceedings of the National Academy of Sciences, has a much longer name than Lucy: It was dubbed Kadanuumuu, which means "big man" in Ethiopia's Afar language. Like the 3.3 million-year-old Lucy skeleton, Kadanuumuu was found in the East African country's Afar region, and shares the species name Australopithecus afarensis.

Australopiths are fossil species that share some traits with chimpanzees - for instance, protruding faces and small brains - but share other traits with humans. Most importantly, their skeletons appear to have been built for upright walking. Arizona State University paleoanthropologist Donald Johanson, who discovered Lucy back in 1974, said the latest discovery adds to a "treasure trove" of hundreds of australopith fossils from East Africa.